This invention relates to a cavity resonator and more specifically relates to changes to the resonant frequency of the resonator and hence changes to the frequency characteristics of the resonator due to temperature variations.
A plurality of coupled cavity resonators can be utilized to form an RF filter with a designed magnitude versus frequency characteristic. Such a filter may be formed from a metal body with separated hollow cavities defining individual resonators enclosed by a cover plate. A tuning mechanism such as metal screws with an adjustable length protruding into the hollow cavities can be utilized to fine tune each resonator to a desired frequency. The physical dimensions of the hollow cavities and the position and length of the tuning screw determines the resonant frequency of the resonator. As the materials of the resonator expand or contract due to changes in temperature, the resonant frequency of the resonator, and hence the magnitude versus frequency response of the filter, will change since the resonant frequency depends on the physical dimensions of the cavity and the position of the tuning mechanism.